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<a name="boost.pfr.get"></a><div class="titlepage"></div>
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<h2><span class="refentrytitle">Function get</span></h2>
<p>boost::pfr::get — Returns reference or const reference to a field with index <code class="computeroutput">I</code> in <a class="link" href="../../boost_pfr/limitations_and_configuration.html" title="Limitations and Configuration"> simple aggregate </a><code class="computeroutput">val</code>. </p>
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<h2 xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv-title">Synopsis</h2>
<div xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv"><pre class="synopsis"><span class="comment">// In header: &lt;<a class="link" href="../../reference_section.html#header.boost.pfr.core_hpp" title="Header &lt;boost/pfr/core.hpp&gt;">boost/pfr/core.hpp</a>&gt;

</span>
<span class="keyword">template</span><span class="special">&lt;</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> I<span class="special">,</span> <span class="keyword">typename</span> T<span class="special">&gt;</span> 
  <span class="keyword">decltype</span><span class="special">(</span><span class="keyword">auto</span><span class="special">)</span> <span class="keyword">constexpr</span> <span class="identifier">get</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">T</span> <span class="special">&amp;</span> val<span class="special">)</span><span class="special">;</span>
<span class="keyword">template</span><span class="special">&lt;</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> I<span class="special">,</span> <span class="keyword">typename</span> T<span class="special">&gt;</span> 
  <span class="keyword">decltype</span><span class="special">(</span><span class="keyword">auto</span><span class="special">)</span> <span class="keyword">constexpr</span> 
  <span class="identifier">get</span><span class="special">(</span><span class="identifier">T</span> <span class="special">&amp;</span> val<span class="special">,</span> 
      <span class="identifier">std</span><span class="special">::</span><span class="identifier">enable_if_t</span><span class="special">&lt;</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">is_assignable</span><span class="special">&lt;</span> <span class="identifier">T</span><span class="special">,</span> <span class="identifier">T</span> <span class="special">&gt;</span><span class="special">::</span><span class="identifier">value</span> <span class="special">&gt;</span> <span class="special">*</span> <span class="special">=</span> <span class="keyword">nullptr</span><span class="special">)</span><span class="special">;</span>
<span class="keyword">template</span><span class="special">&lt;</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> I<span class="special">,</span> <span class="keyword">typename</span> T<span class="special">&gt;</span> 
  <span class="keyword">constexpr</span> <span class="keyword">auto</span> 
  <span class="identifier">get</span><span class="special">(</span><span class="identifier">T</span> <span class="special">&amp;</span><span class="special">,</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">enable_if_t</span><span class="special">&lt;</span><span class="special">!</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">is_assignable</span><span class="special">&lt;</span> <span class="identifier">T</span><span class="special">,</span> <span class="identifier">T</span> <span class="special">&gt;</span><span class="special">::</span><span class="identifier">value</span> <span class="special">&gt;</span> <span class="special">*</span> <span class="special">=</span> <span class="keyword">nullptr</span><span class="special">)</span><span class="special">;</span>
<span class="keyword">template</span><span class="special">&lt;</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> I<span class="special">,</span> <span class="keyword">typename</span> T<span class="special">&gt;</span> 
  <span class="keyword">constexpr</span> <span class="keyword">auto</span> 
  <span class="identifier">get</span><span class="special">(</span><span class="identifier">T</span> <span class="special">&amp;&amp;</span> val<span class="special">,</span> 
      <span class="identifier">std</span><span class="special">::</span><span class="identifier">enable_if_t</span><span class="special">&lt;</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">is_rvalue_reference</span><span class="special">&lt;</span> <span class="identifier">T</span> <span class="special">&amp;&amp;</span> <span class="special">&gt;</span><span class="special">::</span><span class="identifier">value</span> <span class="special">&gt;</span> <span class="special">*</span> <span class="special">=</span> <span class="number">0</span><span class="special">)</span><span class="special">;</span></pre></div>
<div class="refsect1">
<a name="id-1.3.29.9.3.7.4"></a><h2>Description</h2>
<p><span class="bold"><strong>Example:</strong></span> </p>
<pre class="programlisting"><span class="keyword">struct</span> <span class="identifier">my_struct</span> <span class="special">{</span> <span class="keyword">int</span> <span class="identifier">i</span><span class="special">,</span> <span class="keyword">short</span> <span class="identifier">s</span><span class="special">;</span> <span class="special">}</span><span class="special">;</span>
<span class="identifier">my_struct</span> <span class="identifier">s</span> <span class="special">{</span><span class="number">10</span><span class="special">,</span> <span class="number">11</span><span class="special">}</span><span class="special">;</span>
<span class="identifier">assert</span><span class="special">(</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">pfr</span><span class="special">::</span><span class="identifier">get</span><span class="special">&lt;</span><span class="number">0</span><span class="special">&gt;</span><span class="special">(</span><span class="identifier">s</span><span class="special">)</span> <span class="special">==</span> <span class="number">10</span><span class="special">)</span><span class="special">;</span>
<span class="identifier">boost</span><span class="special">::</span><span class="identifier">pfr</span><span class="special">::</span><span class="identifier">get</span><span class="special">&lt;</span><span class="number">1</span><span class="special">&gt;</span><span class="special">(</span><span class="identifier">s</span><span class="special">)</span> <span class="special">=</span> <span class="number">0</span><span class="special">;</span>
</pre>
<p> </p>
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